A 50-rupee banknote, which was in circulation in Seychelles between 1968 and 1973, had the word “sex” incorporated into in its design.

The word can be spotted in palm tree fronds beside an image of Queen Elizabeth. Today 50 rupees is worth about £2.50 – but this note that is to go under the hammer in October has an estimate value of £200.

Mona Lisa

The subject of one of the world’s most famous paintings remains a mystery but in 2010 an Italian researcher revealed high-resolution images of the Mona Lisa’s right eye showed the initials LV were discernible, while her left seemed to feature un-deciphered symbols.

The Beatles

The Beatles created a ‘backmasked’ message, whereby a message is recorded backwards onto a track, for the 1995 recording of John Lennon’s 1977 demo Free as a Bird, released 15 years after his death. It featured Lennon saying “turned out nice again” at the end.

The Lion King

When Simba lies down on the edge of a cliff in The Lion King, a cloud of dust rises and for a few frames appears to form the word “sex”. Some have argued the special effects team intended the message to read SFX to leave their mark on the film.

Museum of London

The Museum of London logo is bright and eye-catching but the designers behind it cleverly managed to represent the geographic area of the capital as it expanded over time – which may be missed by visitors who think it’s just a series of colourful blobs.

The Simpsons

In the original opening credits of The Simpsons, a checkout assistant swipes Maggie on the cash register. The till reads $847.63, supposedly the average monthly cost for raising a child in the US in 1989, according to a survey seen by the show’s co-creator.

The original version of this post can be found here. Pictures were taken from here.